Ext中comboBox跟TreePanel實現(xiàn)下拉樹，關鍵點就是：下拉之前要先清空樹的div ，然后在render上去，如：el = el.parent().dom.innerHTML="";

//start 擴展combobox+treepanel組合

    var el = Ext.get("tree");

    if(el){

       el = el.parent().dom.innerHTML=""; //清空之前樹的div

    }

    var comboxWithTree = new Ext.form.ComboBox({

       store:new Ext.data.SimpleStore({fields:[],data:[[]]}),

       editable:false,

       mode: 'local',

       triggerAction:'all',

       maxHeight: 200,

       tpl: "<tpl for='.'><div style='height:200px'><div id='tree'></div></div></tpl>",

       selectedClass:'',

       onSelect:Ext.emptyFn

    });

    var tree = new Ext.tree.TreePanel({

       loader: new Ext.tree.TreeLoader({

               dataUrl : getAppName()+'/faq/faq_faq/util_faq/getFaqTypeTree.jsp'

            }),

       border:false,

       root:new Ext.tree.AsyncTreeNode({id:'0',text: 'FAQ類型'})

    });

    tree.on('click',function(node,e){

       if ( node.id =='0') {  

            e.stopEvent(); // 如果是根節(jié)點則不觸發(fā)  

            return;  

        }  

        comboxWithTree.setValue(node.text);

       comboxWithTree.collapse(); // 隱藏ComboBox列表

    });

    comboxWithTree.on('expand',function(){

       tree.render('tree');

    });

    comboxWithTree.render('faq_functree_idDiv');

    //end 擴展combobox+treepanel組合